Electric sauna bath heater



March 14, 1967 new ET AL ELECTRIC SAUNA BATH HEATER Filed Jan. 16, 1964HHHLHN mm \m nvvzzmorz Gweoau A4. Dow la W514 7. SWENJO/V MI I, Me- 5 0%Arrwewsxs United States Patent 3,309,503 ELECTRIC SAUNA BATH HEATERGordon M. Dow, North, and Lowell T. Swenson, Thief River Falls, Minn.,assignors to Dow-Key Company, Inc, Thief River Falls, Minn., acorporation of Minnesota Filed Jan. 16, 1964, Ser. No. 338,086

12 Claims. (Cl. 219-378) This invention relates generally to baths andis more particularly directed to apparatus for providing a saunatypebath which originated in Finland.

An object of the present invention is to provide an improved apparatuswhich forms a part of a complete installation which may be installed,for example, within.

the average home and which may 'be constructed so that it may beacquired and installed within the range of prices attractive to theaverage homeowner who is interested in obtaining the benefits of a saunabath located in his own home.

Another object of this invention is to provide equipment for utilizationin a sauna bath which is relatively inexpensive to purchase and operate.

A further object of this invention is to provide improved apparatus foruse in individual enclosures, or cubicles, for providing sauna-typebaths.

A still further object of this invention is to provide an improvedheater apparatus for use in a sauna-type bath.

A further object of this invention is to provide a safe heater apparatusfor a sauna-type bath.

It is a still further object of this invention to provide a heater foruse in a sauna-type bath enclosure which provides a more accuratecontrol over the atmosphere which must be created to enjoy the benefitsof a sauna-type bath.

These and other objects of our invention will become apparent from aconsideration of the appended specification, claims and drawings, inwhich:

FIG. 1 is a side elevational view, partly broken away, of a heater whichmay be utilized in a sauna-type bath installation.

FIG. 2 is a top plan view of the heater shown in FIG. 1.

FIG. 3 is a side sectional view taken along section line 33 in FIG. 1.

FIG. 4 is an electrical schematic drawing illustrating one embodiment ofcontrol circuitry which may be utilized in connection with the apparatusshown in FIGS. 1, 2 and 3. g

FIG. 5 is a perspective sketch of a complete saunatype bath apparatus.

' Referring now to the drawings, and particularly to FIG. 5, there isshown a complete sauna bath installation in which an enclosure,indicated generally by the reference numeral 50, is provided with anaccess door 52 and a platform, shown as a series of steps, 51 upon whichthe user of the sauna bath installation may be seated during the timethe bath is in progress. A heater, indicated generally by the referencenumeral 10, and having a control box assembly 40 adapted for connectionto a suitable source of electrical energy through conductors 14, is inposition below a source of liquid 12, having a valve 13 which is adaptedto regulate the flow of liquid down onto the top of the heater apparatus10. In many uses of our apparatus the fluid used to create the desiredatmosphere may easily be applied manually to the top of heater from asuitable source or container (not shown). Control box 40 is alsoconnected to a wall-mounted temperature responsive means 11 for purposesto be explained below.

As will become apparent from a consideration of the operation of theapparatus shown in FIGS. 1, 2, 3 and 4, explained in detail below, thegeneral operation of the complete sauna bath shown in FIG. 5 is asfollows: the subject, or user, enters enclosure 50' and energizes theheater apparatus 10, through suitable means (not shown) and thetemperature in the enclosure rises to a point determined by the settingof the temperature responsive apparatus 11 and heated air, during thistime, is circulated through heater apparatus 10 by the use of a blower15', which takes air from the lower portion of the room and passes itthrough heater apparatus 10 and vents it back into the room through theplurality of slots 21 shown at the sides of heating apparatus 10. Fromtime to time, and as desired by the subject, suitable amounts of aliquid, for example water, are added to the top of heating apparatus 10and the liquid is immediately vaporized and re-expelled and added to theatmosphere in enclosure 50. The temperature of the air therein is heldat a predetermined level and, as will be explained below, the vapor isgenerated at a substantially constant predetermined temperature so thatthe subject may effect a balance and maintain the desired atmosphere, asdetermined by any particular subject, within the enclosure for as longas is desired.

Referring now to FIGS. 1, 2, and 3 of the drawing, heating apparatus 10is comprised of an outer housing 20 which is open at its top and isprovided with a plurality of louvered slots 21 near the upper outsideperiphery to allow for the escape of heated air as will be explainedbelow. Outer housing 20 is also provided with a plurality of legs 22which are provided and adapted to support heating apparatus 10. Asecond, or inner housing 30 is suitably mounted within outer housing 20.Inner housing 30 may be comprised of suitable material which exhibitslow thermal conductivity. Inner housing 30 is formed with an upwardlyextending opening at its top and with at least one inlet opening 55 andat least one outlet opening 54 at the bottom end. First and secondchambers are defined on the interior of inner housing 30 by the suitablepositioning and fastening of a heating means indicated generally by thereference numeral 25. Heating means 25 is comprised of a substantiallyflat "central portion which extends in proximity to and engages thesides of inner enclosure member 30 so as to define the upper and lowerchambers noted above. A plurality of generally conical protuberances 26extend upwardly from the top surface of the central portion of heatermeans 25 and lie within the upper chamber and enclosure 30. A likeplurality of generally conically shaped protuberances depend downwardlyfro-m the lower surface of the center portion of heater member 25 tofill the lower chamber and inner enclosure member 30. A resistanceheating element is shown positioned in an appropriate channel 27 formedin the center of the center portion of heater member 25. This resistanceheating element may be formed integrally with heater member 25 by asuitable process, for example casting. It has further been noted that asuitable material for heater member 25 is a high temperature alloy ofaluminum which is selected to withstand the normal operatingtemperatures of the heater unit. 'It may further be noted that innerhousing 30 may be comprised of a pluraltiy of layers of material 31 and32 to provide a housing 'which has a low thermal conductivitycoefiicient. For example, layer 31 may be comprised of a suitabledielectric material which has low heat transfer characteristics such aspowdered alumina, asbestos or the like. A condition responsive means 16may be utilized to sense the temperature on the top surface of thecenter portion of heating member 25 and is shown, by way of example, asa snap-acting thermostat which may be utilized to directly control theflow of current to heating element 17 as shown in FIG. 4. A perforatedcover member 24 having a plurality of perforations 41 is shown inposition on the top of the top chamber in inner housing memberfih andthe spaces between the upwardly depending protrusions 26 within theupper chamber may be filled with a suitable material having high heattransfer characteristics, for example, marble chips or aluminum balls orshavings; It should be noted that inner housing 30 is divided into twochambers by suitable mounting means (not shown) for heater member 25which will provide a fluid type seal between the upperand lowerchambers. A control box .40 is attached to outer housing 20 and containssuitable devices and apparatus for providing the interconnectionsbetween the conductors of the various components com-prising ourinvention. Upon becoming familiar with the principles of our invention,and with a consideration of the schematic diagram of FIG. 4, theillustrated apparatus and may others will become apparent to thoseskilled in the art for controlling the operation of our apparatus. InFIG. 4 there is shown a condition responsive means 11, also indicated bythe reference numeral T connected to control box 41 through a pair ofconductors; a pair of terminals14 adapted for connection to a suitablesource. of electrical energy; a pair of conductors 66 connected toblower means 15; a pair of conductors connected to resistance heatingelement17; and a pair of conductors connected to condition responsivemeans '16, also indicated by the reference numeral T A blower 15includes an inlet 56 and an outlet 57 which is shown attached to inlet55 on inner housing member 30 and the flow of air is driven by blower 15as indicated generally by the arrows, through blower 15, into the lowerchamber on inner housing 39, around the staggered downwardly dependingprotrusions 28 on heater member 25, out of outlet opening 54 and aroundthe bottom and up the sides of the inside of housing member 20 andthence through louvered openings 21 into the interior of the enclosurein which the heating apparatus is utilized. It may be desirable undersome circumstances, to maintain a predetermined relationship between thearea of inlet openings 55 and outlet openings 54 to provide forefficient transfer of heat energy to the air as it passes through thelower chamber on inner housing 30. A smaller area on the outlet openingsprovides for a form of time delay which serves to increase thetemperature of the air leaving the outlet opening.

While we have shown and described our heater in a particular embodiment,it is anticipated that other forms of apparatus, such as will be setforth below by way of illustrative examples, will occur to those skilledin the art and it is contemplated that these and other modificationsproperly fall within the scope of our invention.

In one operative embodiment of our invention, apparatus similar to theinner housing was utilized. Suitable legs or support means were attacheddirectly to a housing having a single insulated wall. The upper andlower chambers as illustrated in the drawing were present and thegeneral overall operating characteristics were substantially thesame asnoted above in connection with the illustrated embodiment.

A further modification may be obtained by removing the horizontallyoriented lower portion of inner housing 30 and attaching the outlet ofthe blower directly to the bottom of housing 20. In apparatusconstructedaccording to this modification, the relationship between the inlet andoutlet openings, as noted above, should be retained. The dimensions oflower protrusions 28 may also be modified to place the lower endsthereof in closer proximity to the bottom of housing 20.

In FIG. 4 the schematic drawing shows a pair of terminals 14 connectedacross a suitable source of alternating current and electricalresistance heating element 17 connected in series with conditionrsponsive means 16 and the energization of resistance 17 is controlledthereby. In a like manner blower 15 and condition responsive means 11are connected in series across terminals made in the structure asdisclosed, provided such modi-' 14 and the operation of blower 15 iscontrolled in accordance with the operation of the condition responsivemeans. Both of the condition responsive means 11 and 16 may be suitablethermostats which may be adjustable at the will of an operator.

In operation, it has been determined that a suitable temperature for theenclosure of the sauna bath is not less than F. and up to F. or moredependent on the user and this is controlled, upon energization of theheating apparatus, bycondition responsive means 11 which serve toenergize anddeenergi ze blower 15 in a manner which will maintain theenclosure at the predetermined desired temperature. It has also beennoted that one suitable operating temperature for heatingmeans 25 is arelatively constant 600 F. Heating means 25 not only serves as a sourceof heat energy for the air which is passed through heating apparatus 10by means of blower 15, but also. provides a source of heat energy forvaporizing the liquids adde'd through thetop of the apparatus totheupper chamber of innerhousing ,30. 1 \It is understood that 'suitablemodifications maybe fications come within the spirit and scope of theappended claims. Having now therefore fully illustrated and describedourv invention, what we claim' to be new and desire to protect byLetters Patent is:

1. A heater, for sauna bath enclosures comprising in combination: ahorizontally disposed, substantially planar heating element having aplurality of upwardlyand downwardly extending protrusions formedintegrally therewith; heating means disposed interiorly of said heatingelement; a housing therefor, said housing being adapted to surround andenclose said heating element whereby said housing is divided into upperand lower chambers, each containing corresponding upwardlyand downwardlyextending pluralities of said protrusions, the lower chamber havinginlet and outlet openings for the transmission of air therethrough andthe upper chamber having an upwardly directed opening for receivingliquids to be vaporized and also containing a plurality of saidprotrusions on the heating element; and means for supplying air underpressure connected to saidinlet opening,

2. The apparatus of claim 1 in which the upper chamber is filled withparticles. of material exhibiting good heat transfer characteristics.

3. The apparatus of claim 2 in which the upwardly directed opening inthe upper chamber is covered with a perforated screen.

' 4. The apparatus of claim 1 in which said air supplying meanscomprises a blower mounted on said housing to direct air into the inletopening.

5. The apparatus of claim 1 in which the area of the outlet opening isless than the area of the inlet opening.

6. The apparatus of claim 1 in which the housing is comprised ofmaterial exhibiting low heat transfer characteristics.

7. The apparatus of claim 1 in which the housing is mounted within asecond housing and the second housing includes a plurality of openingsadapted to receive air from the outlet opening on the housing for saidheating element and to vent the same to the atmosphere.

8. The apparatus of claim 1 in which the heating means includeselectrical means and a thermostat is mounted on the surface of saidheating means for maintaining the same at a predetermined temperature.

9. A heater for a sauna type enclosure comprising in combination: aheater comprised of a horizontally disposed substantially planar basemember having a plurality of upwardly and downwardly extendingprotrusions dependent therefrom, said heater including electrical meanstherein for heating the same and temperature responsive switching means,on the upper surface thereof, said electrical heating means andtemperature responsive switching means being connected in seriesintermediate a pair of terminals adapted for connection to av suitablesource;

receive said heater whereby the downwardly depending protrusions areenclosed in a lower chamber and the upwardly extending protrusions areenclosed in an upper chamber, said lower chamber having inlet and outletopenings and said upper chamber having an upwardly directed opening; ablower, including current responsive motor means, connected to directair under pressure into the inlet openings in said lower chamber;further temperature responsive means disposed outside of said enclosureand remotely therefrom; and circuit means interconnecting said motormeans and said further temperature responsive means to said source ofelectrical energy.

10. The apparatus of claim 9 in which the protrusions on the heater arein opposed, staggered rows.

11. The apparatus of claim 10 in which the upper chamber is filled withparticles of material exhibiting good heat transfer characteristics.

12. The apparatus of claim 9 in which the housing is surrounded byafurther housing having an upwardly di- 2 rected opening and an openingadapted to coact and register with the inlet opening in the lowerchamber in said housing and including a plurality of openings in fluidtransmitting relationship with the outlet opening in the lower chamberof said housing.

References (fired by the Examiner UNITED STATES PATENTS 1,686,86010/1928 Hussey 219378 1,932,788 10/1933 Keating 4160 2,096,649 10/ 1937Rassanen. 2,654,018 9/1953 Sandberg 219-378 2,846,692 8/1958 Baurnann4160 FOREIGN PATENTS 63,474 4/ 1941 Norway. 74,066 10/ 1948 Norway.107,901 7/ 1943 Sweden. 122,557 8/ 1948 Sweden. 235,386 7/ 1945Switzerland.

ANTHONY BARTIS, Primary Examiner.

H. K, ARTIS, Assistant Examiner.

1. A HEATER FOR SAUNA BATH ENCLOSURES COMPRISING A COMBINATION: A HORIZONTALLY DISPOSED, SUBSTANTIALLY PLANAR HEATING ELEMENT HAVING A PLURALITY OF UPWARDLY AND DOWNWARDLY EXTENDING PROTRUSIONS FORMED INTEGRALLY THEREWITH; HEATING MEANS DISPOSED INTERIORLY OF SAID HEATING ELEMENT; A HOUSING THEREFOR, SAID HOUSING BEING ADAPTED TO SURROUND AND ENCLOSE SAID HEATING ELEMENT WHEREBY SAID HOUSING IS DIVIDED INTO UPPER AND LOWER CHAMBERS, EACH CONTAINING CORRESPONDING UPWARDLY AND DOWNWARDLY EXTENDING PLURALITIES OF SAID PROTRUSIONS, THE LOWER CHAMBER HAVING INLET AND OUTLET OPENINGS FOR THE TRANSMISSION OF AIR THERETHROUGH AND THE UPPER CHAMBER HAVING AN UPWARDLY DIRECTED OPENING FOR RECEIVING LIQUIDS TO BE VAPORIZED AND ALSO CONTAINING A PLURALITY OF SAID PROTRUSIONS ON THE HEATING ELEMENT; AND MEANS FOR SUPPLYIG AIR UNDER PRESSURE CONNECTED TO SAID INLET OPENING. 